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Bogging at freeway speed, causing heat build up

oldskool67

NAXJA Forum User
Location
CA
A couple of months ago I replaced both the front and rear vacuum harness on my 89 XJ. I also replaced the CCV line. Well, I accidently drove the jeep around the block with the end of the CCV line not attached to the intake ( where it sucks in air ) the vehicle was bogging and made a sound like loud humming. Of course I returned home and correctly attached the line. The bogging and noise stopped with it attached. When I drive it at freeway speeds, especially in OD it boggs unless I drop it down a gear and accelerate. It stills makes the noise on the freeway when under load. Sounds like back pressure. It causes heat build up if climbing a grade for a significant distance. I still need to see if my CAT is partially blocked (that's what it feels like) however it will rev and run in the lower gears. Could the CAT still be partially blocked ? What damage could I have done by driving it a short distance with the vacuum line open ? It didn't make this noise or perform like this before. Thanks for any suggestions. Sorry for the lack of knowledge on my part. I'm still learing
 
You would not have caused any damage with the vac line disconnected. It might cause a driveablility issue but I've run mine for over a week or two and all I got was a strong fuel smell.

You could, however cause some sort of damage with a clogged cat...but nothing permanent. If your exhaust is clogged (CAT) replacing it would solve the issue.

Do a vacuum test on the intake manifold to determine if you have an exhaust blockage. If so, a new cat is usually the fix
 
The only issue you could have from running with the vacuum line disconnected is if you sucked some debris in somewhere and it blocked a line.

Sounds like a blocked cat to me.
 
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